9781422275993

SCIENCE TECHNOLOGY

ELECTRICITY

SCIENCE TECHNOLOGY

ELECTRICITY ELECTRONICS GADGETS & DEVICES INTERNET ROBOTICS SPACE EXPLORATION

SCIENCE TECHNOLOGY

ELECTRICITY

Mason Crest

Mason Crest

Mason Crest 450 Parkway Drive, Suite D Broomall, PA 19008 www.masoncrest.com

© 2019 by Mason Crest, an imprint of National Highlights, Inc.

All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, taping, or any infor- mation storage and retrieval system, without permission from the publisher.

Printed and bound in the United States of America.

Series ISBN: 978-1-4222-4205-6 Hardback ISBN: 978-1-4222-4206-3 EBook ISBN: 978-1-4222-7599-3

First printing 1 3 5 7 9 8 6 4 2

Cover photograph by Gjp311/Dreamstime.com.

Library of Congress Cataloging-in-Publication Data Names: Mason Crest Publishers, author. Title: Electricity / by Mason Crest. Other titles: Electricity (Mason Crest Publishers) Description: Broomall, PA : Mason Crest, [2019] | Series: Science & technology Identifiers: LCCN 2018034422| ISBN 9781422242063 (hardback) | ISBN 9781422242056 (series) | ISBN 9781422275993 (ebook) Subjects: LCSH: Electrical engineering--Juvenile literature. Classification: LCC TK148 .E37 2019 | DDC 621.3--dc23 LC record available at https://lccn.loc. gov/2018034422

QR Codes disclaimer: You may gain access to certain third party content (“Third-Party Sites”) by scanning and using the QR Codes that appear in this publication (the “QR Codes”). We do not operate or control in any respect any information, products, or services on such Third-Party Sites linked to by us via the QR Codes included in this publication, and we assume no responsibility for any materials you may access using the QR Codes. Your use of the QR Codes may be subject to terms, limitations, or restrictions set forth in the applicable terms of use or otherwise established by the owners of the Third-Party Sites.

Our linking to such Third-Party Sites via the QR Codes does not imply an endorsement or sponsorship of such Third-Party Sites, or the information, products, or services offered on or through the Third-Party Sites, nor does it imply an endorsement or sponsorship of this publication by the owners of such Third-Party Sites.

4

SCIENCE & TECHNOLOGY

CONTENTS

Tools and Equipment .

30

introduction . Electric Charge . Static Electricity . Electric Current .

8

Common Electrical Appliances .

32

8

Safety .

34

10

Measuring Instruments . Consumption of Electricity . Alternative Electricity . Conservation of Electricity . text-dependent questions .

36

12

38

Sources of Electricity .

14

40

Conductors and Insulators .

16

42

Magnetism .

18

44

Electromagnetism .

20

research projects .

45

Transformers . 22 Electric Circuits . . . . . . . . . . . . . 24 Electric Motors . 26 Switches . 28

find out more .

46

series glossary of key terms .

47

index .

48

KEY ICONS TO LOOK FOR

Series Glossary of Key Terms: This back-of-the-book glossary contains terminology used throughout this series. Words found here increase the reader’s ability to read and comprehend higher-level books and articles in this field. Research Projects: Readers are pointed toward areas of further inquiry connected to each chapter. Suggestions are provided for projects that encourage deeper research and analysis. Sidebars: This boxed material within the main text allows readers to build knowledge, gain insights, explore possibilities, and broaden their perspectives by weaving together additional information to provide realistic and holistic perspectives. Words to Understand: These words with their easy-to-understand definitions will increase the reader’s understanding of the text, while building vocabulary skills. Educational Videos: Readers can view videos by scanning our QR codes, providing them with additional educational content to supplement the text. Examples include news coverage, moments in history, speeches, iconic moments, and much more! Text-Dependent Questions: These questions send the reader back to the text for more careful attention to the evidence presented here.

5

ELECTRICITY

WORDS TO UNDERSTAND

alloy a metal that is made by combining one or more metals alternative something that can be used in place of something else capacitor a device that stores electricity cautious to be careful chemical reaction a reaction that causes change when chemi- cals combine and form different substances constantan an alloy of copper and nickel contraction a movement of muscles when they become tighter deplete to become less electric shock a painful feeling that a person experiences when electricity suddenly passes through the body emission the act of sending out gases or heat into the atmo- sphere fatal dangerous to life; something that can cause death fluorescent bulb a bulb that produces light when an electric current is passed through it fluctuation to change frequently fossil fuel a fuel that is produced by the burning of fossilized objects like coal, which is made from dead trees and plant matter friction a force that is produced when one object rubs against another object geyser a machine that is used in many households for heating water global warming increase in the temperature of the earth be- cause of the rise in greenhouse gases like carbon dioxide gravitational force a force that makes two objects with mass move toward each other incandescent bulb a bulb that produces light as a result of being made very hot manganin an alloy of copper, manganese, and nickel

6

SCIENCE & TECHNOLOGY

mechanical energy an energy that is produced by an object due to its motion or its position maglev train a high-speed train that runs with the help of magnetic force natural gas a gas that is found inside earth and is used for cooking and heating neon a colorless and odorless gas that shines brightly when electricity flows through it nuclear energy an energy that is stored in the nucleus of at- oms; also known as atomic energy nuclear reactor a machine used for producing nuclear energy in the form of electricity pollution the contamination of air, water, or soil by means of harmful or poisonous chemical substances in the environment porcelain a ceramic substance used for making crockery radioactive element an element that contains very harmful energy that is usually produced during nuclear reactions renewable something that can replace itself by a natural process replenish to enrich resistor a substance that regulates the flow of electric current in an electric circuit by providing resistance smokestack a large chimney through which gases, smoke, and vapors discharge synthetic cloth a type of cloth that is made of synthetic fibers like polyester or nylon thermostat a device used in machines or appliances to control or regulate temperature turbine a machine that contains a wheel that is made to rotate by the extreme pressure of any fast flowing liquid or gas and which produces power welding to heat and hammer metals to give them a desired shape or size

7

ELECTRICITY

Electric Charge

A n electric charge is a basic property of matter. Matter is made up of atoms as its smallest unit. An atom is further divided into electrons, protons, and neutrons. A proton has a positive charge while an electron has a negative charge. Thus, an electric charge is produced when electrons and protons move through an atom.

INTRODUCTION E lectricity is a form of energy that is created by the flow of electric charges. The word electricity was coined by a physician William Gilbert. Electricity is neither a renewable nor nonrenewable source of energy. The concept of electricity is also observed in sever- al creations of nature. Lightning is the most common natural example. Another example, a fish called the electric eel, has a high voltage cur- rent in its cells to catch its prey. In addition to all these examples, all the activities in animal and plant cells take place due to electric stimulation inside the nerve cell. Electricity has several applications in today’s world. It is used to run ap- pliances, such as televisions, com- puters, microwave ovens, washing machines, and more.

Law of conservation of charge

All the electric charges follow a univer- sal law. This is the law of conservation of charges . This law states that the total charge in an isolated system is al- ways constant. Thus, just like energy, charges can neither be created nor destroyed. However, the charges can move and be transferred from one part of the object to another.

8

SCIENCE & TECHNOLOGY

Properties of electric charges Electric charges have several unique properties: ● ● Like charges repel each other, while unlike charges attract.

● ● An electric charge is denoted by the symbol e . It has a value equal to 1.6x10 19 . ● ● Motion of an object does not affect its charge. ● ● Electric charges are always con- served. ● ● The total amount of charge on an object is the sum total of all the charges spread in the different directions of the object.

Inside an atom

Attract

Repel

SCIENCE FACTS

● ● Contraction of heart muscles takes place due to the presence of electric current in the body. ● ● The neutron of an atom is neutral. It does not have any kind of charge on it.

9

ELECTRICITY

S tatic electricity simply refers to the electricity produced by stat- ic charges because of friction be- tween two objects. Static charges are stationary or immovable charges. These charges collect on the up- per surface of an object and remain there unless disturbed. An object acquires a static charge when it is rubbed against another object. Static Electricity

Lightning Rod Benjamin Franklin invented the light- ning rod in 1752. A lightning rod is a metal rod that is placed at the top of a building. The other end of the rod is connected to the ground with a wire. Lightning rods protect buildings from the effects of lightning.

Benjamin Franklin

SCIENCE FACTS

● ● A bolt of lightning can measure up to three million volts (3,000 kv)! ● ● Synthetic clothes develop more static charges than cotton fabrics.

10

SCIENCE & TECHNOLOGY

Lightning Lightning is the discharge of electricity in the atmosphere. It is an example of static electricity. The particles present inside the cloud rub against each oth- er and get oppositely charged. These clouds are then attracted by other clouds or by the surface of the earth. This causes lightning.

Applications Static electricity is widely used in pollution control plants and smokestacks . The dust particles are giv- en a charge and collected on the filter. It is also used in photocopy machines and while painting cars. The ink and spray that have the charged particles are pasted or copied on the material.

11

ELECTRICITY

A n electric current is defined as the amount of charge flowing through a wire at a given time. This form of flowing energy is known as cur- rent electricity. There is just one difference between static electricity and current electricity. Static electricity occurs due to the collection of charges whereas current electricity exists due to the flow of charges. Electricity is measured in amperes and it is denoted by the symbol A. Electric Current

Heating Effect of Electric Current When an electric current is passed through a con- ductor, there is a resistance in the flow of electric current and this generates heat. This heating prop- erty of electric current is used in appliances like electric immersion water heaters, electric irons, etc. All of these have a heating element in them, which is generally made of specific alloys like nichrome, manganin , constantan , etc. A good heating ele- ment has high resistivity and high melting point. An electric fuse is an example of the application of the heating effect of an electric current.

Converting heat to electricity

12

SCIENCE & TECHNOLOGY

SCIENCE FACTS

● ● Alternating current was used for the first time by a French neurologist, Guillaume Duchenne in 1855. ● ● Electricity travels at the speed of about 186 miles (300 km) per second, similar to light.

Types of Electric Current Depending on the flow of charges, electric current is further divided into two types. These are alternating current and direct current. Alternating current, or AC, is the current which changes its flow direction after every fixed time span. On the other hand, direct cur- rent, or DC, is the type of current which does not change its flow direction.

High voltage transmission lines deliver power from electric generation plants over long distances using alternating current.

13

ELECTRICITY

Sources of Electricity E lectricity is the most commonly used form of energy. It is used to light and warm homes, and to run all kinds of machines and appliances. Most of the electricity that we use is obtained by burning coal, petroleum, and natural gas .

Nonrenewable Sources of Energy

Nonrenewable sources of energy are sources that are available in nature in a limited amount. These sources are also known as non- replenish- able sources of energy and need to be used carefully. They include fossil fuels , such as coal, oil, and gasoline. Even nuclear energy is another nonrenewable source of energy. It is produced by the chemical reaction s of radioactive element s in a nuclear power plant. It produces a large amount of energy that is used to produce electricity.

14

SCIENCE & TECHNOLOGY